Purification and Characterization of an Amyloglucosidase from Termitomyces clypeatus That Liberates Glucose From Xylan

Abstract

An amyloglucosidase was purified to homogeneity from the culture filtrate of Termitomyces clypeatus, using the following steps: ammonium sulfate fractionation, DEAE‐Sephadex chromatography, and HP‐GPLC on an Ulstropac TSK‐G3000 SWG column. The enzyme was a glycoprotein with a minimum molecular weight of 56 000. It had appreciable activity on glycogen and amylopectin, moderate activity on maltose, and little activity on panose. The enzyme, unlike fungal amyloglucosidase (Aspergillus niger), could liberate glucose from xylans. The enzyme had Km = 1.81 mg/mL and Vm = 82.1 μmol/min/mg for starch hydrolysis and Km = 4.36 mg/mL and Vm = 57.7 μmol/min/mg for the hydrolysis of larch wood xylan. Among the different inhibitors, NBS and CDTA were the most potent. Previously the enzyme was shown [Khowala, S.; et al. Appl. Microbiol. Technol. 1992, 37, 287–292] to have synergistic activity on xylan hydrolysis similar to other xylanolytic enzymes: α‐arabinofuranosidase or α‐glucuronidase. Since the amyloglucosidase was not active on cellulose, arabinogalactan, or β‐glucans, which may be present as contaminants in xylan, the probable liberation of glucose directly from xylan by the enzyme was indicated.

Optimization of the production of shrimp waste protein hydrolysate using microbial proteases adopting response surface methodology

“…The amino acid composition of hydrolysate samples produced by alcalase hydrolysis after 30, 60 and 90 min were quantified using amino acid analyzer (Waters, USA) by employing PICO.TAG column and work station following method of Ghosh et al 1995. Detection for eighteen amino acids in the sample were done, which were aspartic acid (Asp), glutamic acid (Glu), serine (Ser), glycine (Gly), histidine (His), arginine (Arg), threonine (Thr), alanine (Ala), proline (Pro), tyrosine (Tyr), valine (Val), methionine (Met), isoleucine (Ile), leucine (Leu) and phenylalanine (Phe).…”

Symbiosis With Fungi

“…This type of fungus seems more specialist in that each species is found only in association with one termite species. The group includes the symbiotic fungus of M bellicosus [50] but also T. clypeatus, which is cultivated by just one host, 0. lacustris [118], and produces several constitutive enzymes in vitro [35,36,56,86,102,106,107].…”

Aqueous two-phase extraction coupled with ultrafiltration for purification of amyloglucosidase

“…The most important application of amyloglucosidase is the production of high glucose syrup which is used to produce crystalline glucose and high fructose syrup [14]. Its other commercial applications include production of dextrose for confectionery and pharmaceuticals [15] and liberation of glucose from different xylans [16]. Hence it was chosen as a model enzyme for testing the scheme proposed in the present study.…”